Dental device for obtaining the centric relation of the jaws



Aug. 11, 1964 G. c. REYNOLDS DENTAL DEVICE FOR QBTAINING THE CENTRICRELATION OF THE JAWS Filed Jan. 22, 1962 INVENTOR 3 gmseafiww BY WORNUnited States Patent 3,143,802 DENTAL DEVICE FOR OBTAINING THE CENTRICRELATION OF THE JAWS Grover C. Reynolds, 4401 Charlotte Ave, Nashville,Tenn. Filed Jan. 22, 1962, Ser. No. 167,623 7 Claims. (CI. 32-19) Thisinvention relates to a dental device for obtaining the centric relationof the jaws, and more particularly to such a device which may beuniversally adjustable.

In the conventional method of making a set of false teeth for a patient,impressions of the persons gums are made in soft plastic material suchas wax. A harder stone-like material in molten form is poured into themolds of the gums formed by the impressions and permitted to set to forma stone-like reproduction or model of the edentulous gums. Another pinkplastic material, such as wax, is pressed over the gum surfaces of thestone-like models for both the upper and the lower jaws to form upperand lower base plates. A flat metal supporting plate is then placedagainst the outer surface of each base plate opposite the gum surface insuch a man ner that the metal plates oppose each other in spacedrelation. The upper metal plate has a depending stylus, while the lowermetal plate has a thin layer of wax spread over a small surface directlybeneath the stylus.

The plastic base plates and the supporting metal plates are removed fromtheir respective models and inserted into the mouth of the patient andthe gums inserted into the cavities or impressions of the plastic baseplates. The patient closes his mouth and chews, moving his lower jawlaterally and back and fourth to permit the stylus to trace aconfiguration in the waxed surface on the lower metal plate. In allpatients, the stylus describes a substantially V-shaped path, known as aGothic Arch.

The plastic base plates and the metal plates are then removed from thepatients mouth and the models are replaced in the impressions of thebase plates. With the stylus held in the apex of the Gothic Arch andadjusted to proper elevation, the models are secured to an articulatorby means of plaster of Paris.

In this crude manner, the centric relation of the jaws and gums areobtained preliminary to the making of a set of false teeth for thepatient. The term centric relation refers to the natural relationship ofan upper jaw and a lower jaw of a patient when the jaws are normallyclosed. By nature, the centric relation of any persons jaws is notsymmetrical, nor is it identical to the centric relation of any otherpersons jaws.

It is therefore an object of this invention to provide a pair of supportplates for plastic dental base plates, which support plates may beuniversally adjusted with respect to each other, while in the patientsmouth, and locked in the adjusted position of the plates in order toobtain the true centric relation of the patients jaws.

Another object of this invention is to provide a pair of support platesfor obtaining the centric relation of the jaws, one plate having aplurality of styli, for not only establishing the Gothic Arch, but alsofor orienting the plates in centric relation.

Another object of this invention is to provide a dental device forobtaining the centric relation of the jaws, which is simple andeconomical in structure, and which may be easily and quickly manipulatedin not only obtaining the centric relation of the jaws, but alsotransferring this relationship to the articulator.

Further objects and advantages of the invention will be apparent fromthe following description taken in conjunction with the drawings,wherein:

FIG. 1 is a front elevational view of the invention, mounted on anarticulator in closed position;

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FIG. 2 is a side elevation of the invention disclosed in FIG. 1;

FIG. 3 is a top plan view of the lower support plate;

FIG. 4 is a bottom plan view of the upper support plate; and

FIG. 5 is a section taken along the line 5-5 of FIG. 3.

Referring now to the drawings in more detail, and particularly to FIGS.1 and 2, the upper plastic base plate or bite plate 10, having a surfacecoating of soft wax 11, is formed around a stone-like model 12 of theupper gum of the patient, and secured to the upper surface of the upperfiat metal support plate 13. The upper plate 13 is provided withlaterally extending arms 14 having apertures 15 therethrough, so thatthe arms 14 may be immersed in the soft wax 11 to sustain the uppersupport plate 13 upon the bite plate 10. The apertures 15 permit thesoft wax to seep through the arms 14 to provide a more secure bond. Toassist in accomplishing the same purpose, the periphery of the upperplate 13 is provided with serrations 16.

In a like manner, a lower plastic base plate 19 coated with wax 20, andforming an impression of the lower gum on the lower stone-like model 21,is secured to a lower flat metal support plate 22 by means of laterallyextend ing arms 23 having apertures 24, and serrations 25.

A T-shaped bracket 28 is secured to the bottom surface of the uppersupport plate 13 by any convenient means, such as the bolts 29. Slidablymounted through aligned apertures in the upper plate 13 and the bracket28 are three styli 30, 31 and 32, arranged to slidably reciprocateaxially and substantially normal to the upper plate 13. The bracket 28and the upper plate 13 provide bearings for the axial movement of thestyli 30, 31 and 32. The top of each stylus, 30, 31 and 32, terminatesin an enlarged head 33 which is connected to a coil spring 34surrounding the upper portion of each stylus 30-32 between the head 33and the top of the upper plate 13. The springs 34 are adapted to biasthe styli 30-32 downward through the upper plate 13.

Threaded laterally through the forward edges of the bracket 28 areadjustable set screws 35, 36 and 37, each adapted to lockingly engage acorresponding stylus 30-32 in any axially adjusted position. The axes ofthe set screws 35-37 are substantially normal to the axes of the styli30-32.

The openings 39 (and aligning openings in the plate 13) may be providedin the bracket 28 to receive the styli 30-32 for a patient who has asmall or narrow mouth.

A pair of pivotal posts 41 and 42 extend upwardly from the top of thelower support plate 22 to provide journals for the ends of the threelocating arms 43, 44 and 45. The arms 43-45 are arcuate, being curvedfrom their journaled ends inwardly toward the center of the plate 22.Each of the arms 43-45 is provided, adjacent the inner surfaces of theirfree ends, with a plurality of notches, grooves or serrations 47, asbest disclosed in FIG. 3. FIG. 3 also discloses the location of thethree styli 30, 31 and 32, when they have engaged the top surface of thebottom plate 22 in an adjusted position for a patient. Although the arms44 and 45 are substantially the same length, the arm 43 is somewhatshorter, since it only has to extend from its journaled end to engagethe front stylus 30. Even though the arms 43 and 44 are journaled aboutthe same post 41, and the arm 45 is journaled about a separate post 42,the means of journaling these arms to the plate 22 is not of particularimportance, so long as the arms are mounted to carry out their intendedfunction. The arms 43-45 must be of sufficient length that the serratededge of each of them will engage their corresponding styli 30-32 for anyadjusted position of a patients jaws.

Located on the upper surface of the lower support plate 22 and adaptedto register with the lower pointed end of the stylus 30 is a layer ofwax 50. When the plates 13 and 22 are in operative position and the jawsof the patient are closed, the movement of the jaw will cause the stylus30 to form a' Gothic Arch 51 'inthewax 50."

The operation of the invention is as follows:

After 'the models of the gums 12 and 21 have been poured and set, and'the impressions removed, a plastic material is heated and pressed overthe gum surfaces of the models 12 and 21 to form the plastic base orbite plates ai1d 19. After the biteplates 10 and 19 have hardened,coatings of soft wax 11 and 20 are placed on the outer opposing surfacesof the respective bite plates which are placed the patients mouth. Theupper plate 13 andthe lower plate 22 are then assembled together withthe styli 31 and 32 locked in raised position, and only the stylus 30unlocked to engage the lower support plate 2 2. In this assembledposition, the arms 43-45 remain disengaged from their respective styli30-32. The supportplates 13 and 22 are held together by wire tongs ofany convenient construction and inserted into the patients mouth. Theplates 13 and 22 are generally centered in the mouth so that the softwax 11 and 20 will infiltrate the apertures and 24and mesh with theserrations 16 and 25 of the respective plates. After the upper plate'13has become thus secured to the base plate 10, and the lower supportplate 22 secured to the lower base plate 19, the tongs are removed.

When the mouth, lips and jaws of the patient are in proper verticalrelation, the set screw 35 is tightened to lock the front stylus 30 tothe upper plate 13, so that the pointed end of the stylus 30 penetratesthe wax 50 and touches the upper surface of the lower support plate 22.Thepatient is then requested to chew so that the stylus 30 will form theGothic Arch 51 inthe wax 50. When the patient stops chewing, the stylus30 is located in the apex of the Gothic Arch 51 with the pointed ends oftht styli 31 and 32 resting on the upper surface of the lower supportplate 22. The set screws 36 and 37 are tightened tolock the styli 31 and'32 in these positions, and the arms 43," 44 and 45 are manually pivotedinwardly about their respective posts 41 and 42 until the correspondingnotches 47 engage the respective styli 30- 32.

The threaded posts 41 and 42 are adapted to pass through and hold theirrespective-arms 43-45 in pivotal or locked positions by means of nuts,as disclosed in FIG. 5. After the arms 43-45 engage their respectivestyli 30-32, they may be locked by tightening the posts 41 and 42 in'their'respective nuts." Since this tightening must be done While theplates 13 and 22 are in the mouth, it would be preferable for the posts41 and 42 to slant forward to make the heads of the posts moreaccessible to a screwdriver. The arms 43-45 and plate 22 may be bent atthe proper places to provide for the slanting post's.

Each plate 13 and 22, together with its attached bite plate'10 and 19respectively, is then removed from the patients mouth, either separately'ortogether. The bite plates 10 and '19 are then fitted over theirrespectivegum models 12 and 21. The pointed ends'of the styli 30-32 arethen reinserted in the same notches 47 of their respective arms 43-45which they occupied when in the patients 'mouth." By inserting'thepointed 'end of the stylus 30 back into'th'e apex of the Gothic Arch 51,the three styli will automatically fit into the same notches 47 whichthey occupied-in the patients mouth. The models 12 "and '21 are thenattached to a conventional articulator 55"by means of plaster of Paris56 and 57.

By this means, the jaws and gums of the patient are properly simulatedin true centric relation, and by removing the entire plate assembly andthe base plates 10 and 19, the artificial't'eeth may be made on the gummodels 12 and 19 for the patient in true centric relation.

It will be noted that the upper and lower support plates 13 and 22afford complete universal adjustment. In'the first place, the plates 13and 22 are separated from each other, and in the second place, the threestyli 30, 31 and 32 are arranged in a triangular pattern, each stylusbeing axially adjustable with respect to the upper support plate 13.Thus, the upper plate 13 is permitted to tilt in practically anydirection and about any axis with respect to the lower plate 22. Theaxially slidable styli 30-32 also provide relative vertical adjustmentof the spacing between the plates '13 and 22. The lateral adjustments ofthe plates 13 and 22, that is, from side to side and also backwardandforward, are'm'ade' by generally centering the plates 13 and 22 whenthey are initially placed in the patients mouth. Moreover, the lowerplate 22 is suf ficiently large to permit the styli 30-31 to contact theplate 22 in various lateral positions.

It wi1l be apparent to those skilled in the art that various changes maybe made in the invention, without departing from the spirit and scopethereof, and therefore the invention is not limited by that which] isshown in the drawings and described in the specification, but only asindicated in the appended claims.

What is claimed is: 3

l. A dental device for obtaining the centric relation of jawscomprising: i

(a) a first plate for receiving an impression of one of the gums of thejaws, V

(b) a second plate for receiving an impression of the other gum,

(c) three styli,

(d) means on said first plate mounting said styli in a spaced 'aparttriangular pattern normal to said first plate for axial reciprocationtherethrough,

(e) means on said first plate for locking each stylus in an adjustedaxial position,

(1) means mounted on said second plate movable to ward engagement witheach of said depending styli for locating the laterally adjustedpositions of said styli relative to said second plate when said platesare assembled and the jaws are closed.

2. The invention according to claim 1 in which said locating meanscomprises an arm for each stylus, each arm having a plurality ofnotches, and means permitting movement of each arm toward and away fromits corresponding stylus so that each notch will engage said stylus at adilferent laterally adjusted position.

3. The invention according to claim 2 in which each arm is arcuate andhas one end pivoted to said second pllate, so that each arm will swingacross said second p ate. a

4. The invention according to claim 1 in which apertured arms aremounted on each plate for immersion in soft wax adhering to the biteplates of the dental device.

5. A dental device for obtaining the centric relation of the jawscomprising: a

(a) an upper plate for receiving an impression of the upper gum, andhaving a longitudinal axis extending from front to back,

(b) a lower plate for receiving an impression of the lower gum andadapted to oppose said upper plate when said plates are assembled,

(c) first, second and third styli,

(d) means on said upper plate for mounting said styli normal to saidupper plate for axial reciprocation therethrough,

(e) said first stylus being mounted on said longitudinal axis, and saidsecond and third styli being located substantially equidistant onopposite sides of the longitudinal axis, and behind said first stylus,

(f) means on said upper plate for locking each stylus in an adjusteddepending axial position, and

(g) means mounted on said lower plate movable toward and away from eachstylus to engage andlat- 5 erally locate each corresponding stylusrelative to said lower plate when said plates are assembled.

6. The invention according to claim 5 in which a coil spring for eachstylus is mounted on said upper plate to independently bias each stylustoward said lower plate when said plates are assembled.

7. The invention according to claim 5 in which the means for lockingeach stylus comprises a set screw movably mounted adjacent each stylusfor engagement and disengagement therewith.

References Cited in the file of this patent

1. A DENTAL DEVICE FOR OBTAINING THE CENTRIC RELATION OF JAWSCOMPRISING: (A) A FIRST PLATE FOR RECEIVING AN IMPRESSION OF ONE OF THEGUMS OF THE JAWS, (B) A SECOND PLATE FOR RECEIVING AN IMPRESSION OF THEOTHER GUM, (C) THREE STYLI, (D) MEANS ON SAID FIRST PLATE MOUNTING SAIDSTYLI IN A SPACED APART TRIANGULAR PATTERN NORMAL TO SAID FIRST PLATEFOR AXIAL RECIPROCATION THERETHROUGH, (E) MEANS ON SAID FIRST PLATE FORLOCKING EACH STYLUS IN A ADJUSTED AXIAL POSITION, (F) MEANS MOUNTED ONSAID SECOND PLATE MOVABLE TO WARD ENGAGEMENT WITH EACH OF SAID DEPENDINGSTYLI FOR LOCATING THE LATERALLY ADJUSTED POSITIONS OF SAID STYLIRELATIVE TO SAID SECOND PLATE WHEN SAID PLATES ARE ASSEMBLED AND THEJAWS ARE CLOSED.